Yes, HEROINS is a Scrabble word!

Letter values in Scrabble US: H 4, E 1, R 1, O 1, I 1, N 1, S 1.

Is it a valid word?

HEROINS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a narcotic that is considered a hard drug; a highly addictive morphine derivative; intravenous injection provides the fastest and most intense rush

Also: diacetylmorphine.